Cleaned out the K&N air filter and reoiled. cleaned all the dirt and mud out of air box. Went riding and now it smokes grey smoke when starting up and gets better at idle but with rpms starts smoking again. untill fully warmed up. after that smells oily at full rpms running down the road. Not sure if its related or not. Changed the oil about 2 weeks ago as well and installed new spark plug. old one looked oily as well. Has been running fine until I cleaned the air cleaner. Am I seeing a leaky valve stem seal or bad rings. Any suggestions